"I got some air line tubing that people usually use in their tank and just placed it around the goldfish. I added some valves to the bottom of it, which acted as a 'chair' to prop him up. I added weights to the bottom of the 'chair' and something to keep him afloat on top [styrofoam], and slowly removed pieces until I achieved just the right buoyancy to make it easy for him to swim around without feeling like he's dragging around a chair."

"Think of goldfish as the pugs of the fish world," Derek added. "Pugs have unique features due to the way they were bred, but it also causes them a lot of medical problems - same with goldfish!"

Derek's friend Taylor Dean, who makes a living from educational animal videos on YouTube, tweeted about the wheelchair which has been shared 26,000 times.